The invention relates to a chuck for holding a workpiece comprising a plurality of components to be singulated Such a workpiece may be the molded strip of a clip-array semiconductor Chip Scale Packages (CSP) substrate, and each component may be a CSP.
Conventionally, a number of CSPs are manufactured on a single strip of molded substrate comprising a plurality of such packages, and it is necessary to separate them into singulated packages before further processes to manufacture a CSP can be performed. When singulating the CSPs, for example, by using a dicing saw, it is usual to use a chuck to hold the molded substrate of CSPs in place during the cutting process.
One way of holding the CSP package is by the use of water frame and UV adhesive tape to hold the CSP substrate in place during the singulation, which binds all the individual packages to the adhesive surface during the cutting process. However, as the dicing blade will come into contact with the adhesive tape during cutting, some adhesive will bond to the blade and reduce its effectiveness. Another disadvantage of this process is that there may be adhesive still remaining on the package even after it is removed from the tape. It may become a source of contaminant for the rest of the manufacturing processes.
Another way is to use a chuck with a suction device, similar to that described in U.S. Pat. No. 5,803,797 for a xe2x80x9cMethod and Apparatus to Hold Integrated Circuit Chips onto a Chuck and to Simultaneously Remove Multiple Integrated Circuit Chips from a Cutting Chuckxe2x80x9d. In a fixture based singulation process employing a saw, chip-array electronic packages of a CSP substrate are cut to their individual dimensions and separated from one another on a vacuum chuck with an elastomeric surface. The edge scrap of the CSP substrate will be washed away from the cutting chuck by coolant and cleaning water generated in association with the dicing saw. The sawn CUP will be held onto the chuck until the cutting process is completed and ready to be unloaded to next handling process.
A variant using a similar method is U.S. Pat. No. 6,250,990 for a xe2x80x9cCSP Plate Cutting Apparatusxe2x80x9d. It describes an apparatus for cutting CSP substrates into individual CSPs to put them on carrier trays for transportation. The jig for holding the substrate has numerous suction ports to hold each CSP to be singulate, and also second vacuum line to hold the sawn CSP for subsequent handling as the chuck is removed from the vacuum table.
However, during the singulation process by dicing saws edge scraps or chaffs are released as they are cut and removed from the rest of the workpiece. There is a possibility that some scraps may fly off and hit the saw blade during the cutting process. This can premature blade breakage. The risk is more pronounced when gang saws or multiple-blade dicing methods are used for the cutting process. The prior art mentioned above does not address this problem of controlling edge scraps generated during the singulation process.
It is thus an objective of the invention to seek to provide a chuck that can obviate tho disadvantages of the prior art.
According to a first aspect of the invention, there is provided a chuck for holding a workpiece having a plurality of components to be singulated and chaff areas of the components, comprising means to hold the chaff areas when the components are being singulated.
According to a second aspect of the invention, there is provided; method of dicing a workpiece comprising a plurality of components held to a chuck, and removing chaff areas of the workpiece, including the steps of providing a first pressure means to hold each component of the workpiece to the chuck; providing a second pressure means to hold the chaff areas to the chuck; and dicing the workpiece to separate the plurality of components, and the chaff area.
It will be convenient to hereinafter describe the invention in greater detail by reference to the accompanying drawings which illustrate one embodiment of the invention. The particularity of the drawings and the related description is not to be understood as superseding the generality of the broad identification of the invention as defined by the claims.